Validation is a policy decision, not a yes/no sticker
Some domains accept every SMTP probe, some block probes, and some addresses are technically valid but risky for bulk sending. WillItInbox separates valid, invalid, risky, catch-all, disposable, role, typo, and unknown evidence so your product or campaign can choose the right action.
| Result | What it means | Typical action |
|---|---|---|
| valid | Evidence suggests the mailbox can receive mail. | Accept, but keep monitoring bounces. |
| invalid | Syntax, DNS, MX, or mailbox evidence fails. | Suppress before sending. |
| risky | Catch-all, role, disposable, or policy signals need context. | Segment or review before volume. |
| unknown | The provider did not produce reliable evidence. | Retry later or send conservatively. |